On 16.03.16 09:46, Glenn Linderman wrote:
On 3/16/2016 12:09 AM, Serhiy Storchaka wrote:
On 16.03.16 08:34, Glenn Linderman wrote:
 From the PEP 263:

More precisely, the first or second line must match the regular
    expression "coding[:=]\s*([-\w.]+)". The first group of this
    expression is then interpreted as encoding name. If the encoding
    is unknown to Python, an error is raised during compilation. There
    must not be any Python statement on the line that contains the
    encoding declaration.

Clearly the regular expression would only match the first of multiple
cookies on the same line, so the first one should always win... but
there should only be one, from the first PEP quote "a magic comment".

"The first group of this expression" means the first regular
expression group. Only the part between parenthesis "([-\w.]+)" is
interpreted as encoding name, not all expression.

Sure.  But there is no mention anywhere in the PEP of more than one
being legal: just more than one position for it, EITHER line 1 or line
2. So while the regular expression mentioned is not anchored, to allow
variation in syntax between emacs and vim, "must match the regular
expression" doesn't imply "several times", and when searching for a
regular expression that might not be anchored, one typically expects to
find the first.

Actually "must match the regular expression" is not correct, because re.match() implies anchoring at the start. I have proposed more correct regular expression in other branch of this thread.

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